ColecoVision repair attempt - No video displaying - Electronics novice, looking for advice

[Drajikore]

I am currently trying to fix a ColecoVision that my uncle dug out of storage and donated to me last year. I've only just made the time to give it some attention in the last month or so, and as one might expect, I'm running into some difficulties.

FULL DISCLAIMER: I am a complete amateur when it comes to electronics repair. The extent of my experience is putting PCs together, and once replacing a capacitor on a Sega CD. 

Needless to say, layman's terms are appreciated when possible, and I may be slow to understand advice.

I also don't have a ton of time to dedicate to this project, definitely more of a side-hobby right now, so it may take a frustratingly long time for me to give feedback on what has and hasn't worked, so please bear with me.

 

As I mentioned, the device has been left in storage for decades now. Unfortunately, it was not treated with great care either, as my uncle kept it in his outdoor shed...

In fact, when he dropped it off last year, it was dripping with water that has pooled inside it, likely from melted snow.

Yeah. Bad start.

So I have gone into this repair with full expectation that it may never function again, but wanted to give it my best shot.

I figured there is a slender hope it still worked since it has been disconnected from power for so long, that even the capacitors should have been drained before being water damaged, reducing the risk that anything shorted out.

 

WHAT I'VE DONE SO FAR

I've disassembled it and cleaned the motherboard and connections (and the plastic casing for that matter) quite thoroughly with rubbing alcohol. It was pretty damn dirty, I will post pictures and videos later. 

I did not unsolder anything off the board, including the casing to the power switch or the (I'm presuming?) RF switcher, but I tried my best to visually inspect the inside of the casings, and it looked clean.

I then tossed some silica packs onto the board and under it, then closed it up inside it's cade and left it for a week or two like that, just to try get rid of any moisture.

 

PROBLEMS

After reconstructing it, I've hooked it up, and power seems to cycle through; however, there is no video coming through. The TV static intensifies, so it's clearly trying to feed some kind of signal through, but there no imagery or colour.

 

SOLUTIONS?

From what I have seen online (and how I came across this forum to begin with), the most likely defect is the power switch due to the lubricant drying out and the console failing to draw enough power. I plan to try clean and re-grease the components as my first effort, and if that fails I'll resort to soldering on a new switch (not excited to do that...).

I've also read that this could be due to the RAM being fried, and that a good work around is to install the F18A mod, to bypass the RAM and get a nicer, VGA signal anyways. Won't try this until the MkII is released, but considering trying this if the power switch doesn't resolve anything.

 

With the previous water damage, it's hard to pinpoint what the problem is specifically.

If you guys have any other suggestions on what might be wrong and what may fix it, I'd be happy to hear it!

I'll do my best to provide further troubleshooting details as requested.

[ChildOfCv]

Is the TV on the same channel that the channel selector switch is set for?

 

Also, are you using the original RF box or are you using an RCA cable and coax adaptor?

 

When you look at the circuit board, do you see traces that seem to have disappeared?  As long as a device is unpowered, it takes a while for relatively clean water to destroy it.  But it will still happen given enough time.

Edited August 19, 2020 by ChildOfCv

[Drajikore]

49 minutes ago, ChildOfCv said:

Is the TV on the same channel that the channel selector switch is set for?

 

Also, are you using the original RF box or are you using an RCA cable and coax adaptor?

 

When you look at the circuit board, do you see traces that seem to have disappeared?  As long as a device is unpowered, it takes a while for relatively clean water to destroy it.  But it will still happen given enough time.

Yes, and I tried flipping the switch multiple times while on channels 3 & 4 respectively, as well as channel 2 & 5 for good measure. As expected, it gets the strongest signal when it is on the channel it is set to, but it still just essentially intensified static trying to make shape.

 

I am using a RF switch from an NES/SNES. I tested it with my Intelivision and it works perfectly fine.

I couldn't find the original RF box when I tested it earlier, but after searching online to see what it looks like, I am pretty confident I have it stowed away somewhere. So I will definitely try it again with the original box once I find it.

 

I will have to take a closer look later, but I don't recall seeing any obvious deterioration of any traces on the board, and I was scrutinizing pretty hard since I was trying to clean off all of the dirt and grime to ensure no connections were being made that would accidentally short it.

[ChildOfCv]

You can forego the box entirely in favor of the adaptor I mentioned.  One type is a coax to RCA male, which you'd plug in on the console side and use coax the whole way to the TV.  The other is coax to RCA female which threads to the TV and then connects an RCA cable to the console.  As to which one works best, that may be an area of experimentation.  I had good luck with the console, but others report best results through RCA cable.  It should be shielded RCA video cable if you use that.

 

https://www.amazon.com/RFAdapter-Connector-Convertor-Commodore-Colecovision/dp/B07VWQF6WS

https://www.amazon.com/Cmple-F-Type-Jack-Plug-Adapter/dp/B004KA2G62

I thought the NES one needed power in addition to signal provided on the input.

[NIAD]

I would venture a strong guess that using a NES/SNES RF switch is the problem. The CV doesn’t play very nice with RF switches made for other systems especially if they are newer than the CV and auto-switching.

 

if you can’t find the CV RF, buy an RF-to-Coaxial adapter.

[Drajikore]

Hrm, I'll give the converter a try, as that will make hookup a lot easier for all of the other consoles too.

For testing purposes I'll try it with the original RF switch as @NIAD mentioned as well.

 

As to the NES/SNES RF switch, nope, no power required.

[Drajikore]

I can't seem to edit the OP, but here are a few photos of the condition it was in prior to cleaning. Not very helpful for troubleshooting specifically, but as a frame of reference for how much damage it might have sustained.

[ChildOfCv]

7 hours ago, Drajikore said:

Hrm, I'll give the converter a try, as that will make hookup a lot easier for all of the other consoles too.

For testing purposes I'll try it with the original RF switch as @NIAD mentioned as well.

 

As to the NES/SNES RF switch, nope, no power required.

You misunderstand.  I'm pretty sure power to the RF for NES is supplied over the same cable as the signal from the NES.  In networking, "Power over Ethernet" uses the same idea.

[doubledown]

I have also, over the years, encountered this problem of trying to use these "auto-switching" RF switches like this...with older consoles.  Find/try/use a manual type RF switch, or a direct Phono to Coax cable (to eliminate the need for the switch), before you run around in circles chasing your tail.  I'm not saying 100% that the ColecoVision can't/won't work with these auto-switches...but just eliminate it from the equation for sanity's sake.  

[Drajikore]

8 hours ago, ChildOfCv said:

You misunderstand.  I'm pretty sure power to the RF for NES is supplied over the same cable as the signal from the NES.  In networking, "Power over Ethernet" uses the same idea.

Ah, my mistake, I believe I understand now. That makes more sense to me now why it might be a factor in this.

 

I managed to find both the original RF switch for the CV, as well as a coax-to-RCA-male converter stashed away, but didn't have time to actually hook anything up. Will give it a try at lunch, looking forward to the results. Would be very gratifying if that is all that was wrong.

[Drajikore]

Welp, unfortunately that didn't seem to fix it. Definitely got a stronger signal and not seeing static, but still not able to make out any graphics, colours, or audio - just big white sections on the screen and noise. 

I was going to take a picture/video, but stupid me knocked the power supply off the TV unit, and now it doesn't seem responsive =_= So I'll have to see how much damage I did to that later.... UGH.

 

Otherwise, unless I hear any other helpful suggestions, my next course of action is going to be looking at the power switch, cleaning it and greasing it. 

[Ikrananka]

2 minutes ago, Drajikore said:

... my next course of action is going to be looking at the power switch, cleaning it and greasing it. 

That's a good idea anyway and will at least help eliminate that as a potential source of the problem.  Make sure you give the contacts a good clean and use dielectric grease.  BTW - do you have a multimeter?

[Drajikore]

Just now, Ikrananka said:

That's a good idea anyway and will at least help eliminate that as a potential source of the problem.  Make sure you give the contacts a good clean and use dielectric grease.  BTW - do you have a multimeter?

Sort of, it's a cheap and crappy one and I've never been quite sure how it works (or frankly if it works). So I may invest in a new one if need be.

[Ikrananka]

4 minutes ago, Drajikore said:

Sort of, it's a cheap and crappy one and I've never been quite sure how it works (or frankly if it works). So I may invest in a new one if need be.

Might be a good idea to help with troubleshooting.  You'll at least then be able to measure voltages around the switch and at different locations around the board.  That way you'll also be able to quantify the benefit of cleaning the power switch.

[zaphro72]

1 hour ago, Drajikore said:

Welp, unfortunately that didn't seem to fix it. Definitely got a stronger signal and not seeing static, but still not able to make out any graphics, colours, or audio - just big white sections on the screen and noise. 

I was going to take a picture/video, but stupid me knocked the power supply off the TV unit, and now it doesn't seem responsive =_= So I'll have to see how much damage I did to that later.... UGH.

 

Otherwise, unless I hear any other helpful suggestions, my next course of action is going to be looking at the power switch, cleaning it and greasing it. 

The power supply could be part of the issue if it is an original one that was never rebuilt

[Drajikore]

1 hour ago, zaphro72 said:

The power supply could be part of the issue if it is an original one that was never rebuilt

True enough, it is definitely the original unit and untampered with. Do CV PSUs commonly die out, or is that just a general PSU issue of such old age?

Not all too sure what to l'd be be looking for other than blown capacitors or otherwise broken components from the drop. I'll try follow along with a disassembly guide online.

[zaphro72]

3 hours ago, Drajikore said:

True enough, it is definitely the original unit and untampered with. Do CV PSUs commonly die out, or is that just a general PSU issue of such old age?

Not all too sure what to l'd be be looking for other than blown capacitors or otherwise broken components from the drop. I'll try follow along with a disassembly guide online.

Pretty sure US Colecovision power supplies are know to have quite a few issues, Canadian ones less so I believe, but I am not expert.

[ChildOfCv]

Unfortunately, the CV power supply is welded together so you have to dremmel it apart to look at the inside.  If you do, look for fluid stains around the large capacitors or bulging tops.  If either of those are present, the capacitor needs to be replaced.  If it's leaking, the fluid is corrosive so you should also clean it up.

 

Otherwise you may want to consider one of the alternative CV power supplies available now.

[Drajikore]

10 hours ago, ChildOfCv said:

Unfortunately, the CV power supply is welded together so you have to dremmel it apart to look at the inside.  If you do, look for fluid stains around the large capacitors or bulging tops.  If either of those are present, the capacitor needs to be replaced.  If it's leaking, the fluid is corrosive so you should also clean it up.

 

Otherwise you may want to consider one of the alternative CV power supplies available now.

Wow, hrm, that may be beyond both my toolkit and my skill set for the time being. As much as I would like to eventually fix that PSU, that might be a project for the future.

 

For now, yeah, I think I'll have to resort to tracking down another PSU solution. I'm all ears to any recommendations, but otherwise I'll just do a bit of scouring through this other thread. First thing I am seeing is the ColUSB, will likely pick that up unless I see any better alternatives.

 

 

[doubledown]

I use an arcade power supply from HAPP for my ADAMs and ColecoVisions.  It has the proper voltages and more than enough amperage for either.  Basically you would just need to cut the 4 pin connector and cable off of the original power supply and wire it to the new power supply's screw terminals.  They dont have on/off switches built into them so you can either plug it into a power strip and use its on/off switch, or open up the power supply and add a switch inline on the incoming AC side, which is what I did on mine.  I think they cost like 20 or 30 bucks...and they're robust, and built to last.  Ive been using mine for about 12 years now.

[Drajikore]

Was only able to do some basic troubleshooting today, but made a few small discoveries. As it turns out the PSU is totally fine, it just so happened that I dropped it while I was just about to test one of the RF switches which was actually broken. So that's MY BAD. I used the multimeter on the PSU and got appropriate readings from all the leads (+5V, -5V, and the +12V). Well, I think the 12V anyways, my multimeter is analog, so it was hard to accurately tell anything above 10V.

Couldn't figure out how to get amps readings from my multimeter though, admittedly I'm unsure if it can. Like I say, I'm a novice with electronics.

But I'm less suspicious of the PSU itself now, when I find more time I will open up the console again and get a reading of the voltage actually coming through to the console, as well as clean/re-grease that switch like I keep intending to do.

Lastly, here is a shot of the type of picture it is outputting, if it makes any difference.

[Drajikore]

1 hour ago, doubledown said:

I use an arcade power supply from HAPP for my ADAMs and ColecoVisions.  It has the proper voltages and more than enough amperage for either.  Basically you would just need to cut the 4 pin connector and cable off of the original power supply and wire it to the new power supply's screw terminals.  They dont have on/off switches built into them so you can either plug it into a power strip and use its on/off switch, or open up the power supply and add a switch inline on the incoming AC side, which is what I did on mine.  I think they cost like 20 or 30 bucks...and they're robust, and built to last.  Ive been using mine for about 12 years now.

If it does turn out to be a PSU issue, my first course of action will be to order some replacement parts for the broken one and try repair it, then resort to the ColUSB if it's still in stock by that point.

If that fails, then I like your method as the next approach, hah.

[ChildOfCv]

Well, the amps reading is not easy to make anyway.  You'd have to put the black lead into the power plug, then the read lead attaches to the pin in the CV that the power plug would connect to.  Then you'd have to attach the other 3 wires directly.  Most of the time it doesn't matter anyway.  We don't have a "this many amps" test case to compare with.

 

 

Remove the metal cap on the RF box.  With the black probe on the red arrow above, what voltage do you measure with the red probe at the purple arrow?  And with the red probe at the yellow arrow?

[Drajikore]

On 8/21/2020 at 8:56 PM, ChildOfCv said:

Well, the amps reading is not easy to make anyway.  You'd have to put the black lead into the power plug, then the read lead attaches to the pin in the CV that the power plug would connect to.  Then you'd have to attach the other 3 wires directly.  Most of the time it doesn't matter anyway.  We don't have a "this many amps" test case to compare with.

 

 

Remove the metal cap on the RF box.  With the black probe on the red arrow above, what voltage do you measure with the red probe at the purple arrow?  And with the red probe at the yellow arrow?

Sorry for the delay, busy weekend.

So to start, I re-measured the readings from my PSU, and... I am getting new readings >.<

My +5V line is only giving out 4V and the 12V line is only giving less than 10V now.

When I power it on and take readings, the 4V and -5V remain the same, but the <10V becomes ~7V.

 

With that in mind, these are the readings I got from the nodes you asked about.

 

Purple = 7V

Yellow = 4V

 

I'm guessing that purple should have been 12V and yellow 5V?

I'll order some parts for the PSU off Console5.com to try fix it, and get the ColUSB for good measure.

I'll also clean the switch and get back to you with the new readings after that, as I suspect that if the switch has dirty contacts or isn't making a full connection, that's part of why I might be losing voltage from the 12V line.

[Drajikore]

Welp, the switch definitely needed cleaning, but unfortunately there was no change whatsoever in the readings. Still dropping down to ~7V on the 12V line when power is on.